Substrate processing apparatus and substrate processing method

A substrate processing apparatus comprising:

• a housing having a process space;
• a support unit configured to support a substrate in the process space;
• a gas supply unit to supply process gas to the process space;
• a dielectric plate disposed to face the substrate supported by the support unit in the process space;
• an upper electrode spaced apart from the dielectric plate while surrounding the dielectric plate when viewed from a top;
• and
• a controller,
• wherein the support unit includes:
• a chuck having a support surface to support the substrate and connected with a power source;
• and
• a lower electrode disposed to face the upper electrode while surrounding the chuck when viewed from the top,
• wherein the gas supply unit includes:
• a first gas supply part configured to supply the process gas to a central area of the substrate supported by the chuck;
• a second gas supply part configured to supply the process gas through a space between the dielectric plate and the upper electrode which are provided on an edge area of the substrate supported by the chuck;
• and
• an insulating ring interposed between the chuck and the lower electrode,
• wherein the support unit, the dielectric plate, and the upper electrode are provided, such that a volume of a space, in which the process gas supplied by the gas supply unit flows, is larger in the edge area of the substrate supported by the chuck than the central area of the substrate supported by the chuck, when viewed from the top,
• wherein the controller is programmed to control the gas supply unit such that only the first gas supply part among the first gas supply part and the second gas supply part supplies the process gas, when processing the edge area of the substrate supported by the chuck,
• wherein the insulating ring is in direct contact with the chuck and the lower electrode, and includes a stepped portion on which the lower electrode penetrates into the insulating ring, such that, when viewed from the top, the lower electrode overlaps with the insulating ring in the stepped portion, and
• wherein the insulating ring and the lower electrode are spaced apart from a bottom surface of the edge area of the substrate supported by the chuck.